reading-notes

JavaScript Error handling and debugging

• the stack
  • since JS is interpreted one line at a time, if a line requires info from another line it stacks the new function on top of the current task
• exceptions
  • when errors occur in JS an exception is thrown
  • the interpreter then looks for exception handlers
  • if none are found the code stops execution
  • if an exception handler is present the code is run and the program continues
• error objects are created to help identify and solve errors for the developer
  • Error
    • generic error type, all other errors are based on this
  • SyntaxError
    • proper syntax was not used
  • ReferenceError
    • attempted to use an undefined/unavailable variable
  • TypeError
    • improper data type used, cannot be coerced
  • RangeError
    • numbers not in allowed range
  • URIError
    • encodeURI() decodeURI() improperly used
  • EvalError
    • eval() improperly used

Exception handling

• Try
  • try this code
• catch
  • if this error happens, do this
• finally
  • after all that, do this the above are used to catch errors and prevent your script from crashing, also to give the user feedback and what they are doing wrong